Iran is a country with a rainfall of less than one third of the global average rainfall. Based on all indicators of the water crisis, Iran is in critical condition or on the threshold of a water crisis. In order to manage the crisis, in addition to managing water consumption, it was also necessary to seek new water resources. In these conditions, the production of sewage is relatively stable and not affected by drought conditions. Sewage disposal or reuse is required to be treated. But current filtration systems are very expensive to reduce the burden of microbial contamination and are not applicable in small communities and industries. Natural purification methods are one of the solutions to this problem. One of the most common natural purification methods is constructed wetlands. In this research, the performance of hybrid constructed wetland with pumice and vetiver on urban wastewater has been investigated. The combination of Pumice as a porous material with the ability to absorb the elements as well as vetiver plant as a plant capable of phytoremediation has a significant performance. In this study, ponds were constructed with 0.75 m width, 0.5 m depth and 6 m length and were designed in the vicinity of wastewater treatment lagoon of Isfahan University of Technology. In order to evaluate the performance of constructed wetland, the effects of three and six days retention time (HRT) were studied using a Randomised complete design. On average, during the three days of retention time, the total coliform, fecal coliform, COD, BOD 5 , nitrate, ammonium, TS, TDS and phosphate were 98.99, 99.08, 42.69, 26.92, 20.83, 35.11, 11.31, 9.05 and 5.42 percent decreased respectively. Also, the average duration of six days retention time, the total coliform, Fecal coliform, COD, BOD 5 , nitrate, ammonium, TS, TDS, and phosphate were 99.75, 99.79, 88.89, 37.36, 60.78, 70.53, 13.18, 11.39 and 12.51 percent decreased respectively. In total, the constructed wetland with the mentioned characteristics was successful in remove total coliform, fecal coliform, COD, BOD 5 , and ammonium, and it was acceptable to remove other parameters. Keywords: Hybrid constructed wetland, Vetiver, Pumice, Wastewater
